WASHINGTON (AP) — Spinning off from the special counsel's Russia probe, prosecutors are ramping up their investigation into foreign lobbying by two major Washington firms that did work for former Trump campaign chairman Paul Manafort, according to people familiar with the matter.

The investigation had been quiet for months since special counsel Robert Mueller referred it to authorities in Manhattan because it fell outside his mandate of determining whether the Trump campaign coordinated with Russia.

But in a flurry of new activity, Justice Department prosecutors in the last several weeks have begun interviewing witnesses and contacting lawyers to schedule additional questioning related to the Podesta Group and Mercury Public Affairs, the people familiar with the inquiry said. They spoke to The Associated Press on condition of anonymity because they were not authorized to discuss the ongoing work.
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Podesta is a longtime Democratic operative whose brother, John Podesta, ran Hillary Clinton's 2016 presidential campaign; Weber is a former Republican congressman from Minnesota. Neither man has been charged with any crimes. Their firms have defended the decisions by saying they relied on the advice of outside attorneys.

Mueller's referral also involved Greg Craig, a former White House counsel for President Barack Obama. Craig supervised a report authored on behalf of the Ukrainian government, and Mueller's team has said Manafort helped Ukraine hide that it paid more than $4 million for the work. CNN reported in September that prosecutors were weighing charges against Craig.